1. Field of the Invention
The present invention relates to a source driver, a display device using the same and a driving method of the source driver, and more particularly, to a source driver utilizing a plurality of driving channels, each of which is responsible for outputting a plurality of data driving voltages with same polarity during different scan periods, to perform dot inversion on a display panel.
2. Description of Related Art
FIG. 1 is a schematic diagram of a liquid crystal display (LCD) device. The LCD device 100 includes a gate driver 110, a source driver 120 and a display panel 130. The display panel 130 includes a plurality pixel cells 131 arranged in array manner, and each pixel cell 131 is coupled to one of the scan lines 131 and one of the data lines 121. When a certain scan line 131 is asserted by the gate driver 110, the source driver 120 provides the driving voltages to the pixel cells 131 on the certain scan line 131 via the data lines 121. The source driver 120 is an important component in the driving system of the LCD device 100, which converts a digital data signal corresponding to the pixel cell 131 into the driving voltage, and provides the driving voltage to the pixel cell 131 for controlling the rotation of the liquid crystal corresponding to the pixel cell 131.
As known, the rotation direction of the liquid crystal is related to the electric field direction applied on the liquid crystal. In order to eliminating the DC residual voltage stored within the liquid crystal and avoiding the polarization of the liquid crystal, the LCD device 100 should be driven by polarity inversion. That is to say the driving voltages with different polarities, e.g. positive polarity and negative polarity, are alternatively provided to the pixel cell 131 in different frame periods. There are several kinds of polarity inversion, e.g. column inversion, row inversion, frame inversion and dot inversion.
Referring to FIG. 1, with regard to dot inversion, two adjacent pixel cells 131 are driven by the driving voltages with different polarities, wherein “+” is denoted as positive polarity and “−” is denoted as negative polarity. Each driving channel of the source driver 120 should respectively provide the driving voltage with positive polarity and the driving voltage with negative polarity in two sequential scan periods. The voltage swing range between the positive polarity voltage and the negative polarity voltage is high and results in increasing power consumption of the source driver 120 and temperature of the LCD device 100.
Performing column inversion or frame inversion on the LCD device 100 can save power since each driving channel of the source driver provides the driving voltages with same polarity in different scan periods. However, the LCD device 100 driven by dot inversion still has better display quality than that driven by others due to several advantages, such as low occurrence probability of cross talk and flicker. Therefore, considering with the driving of dot inversion, the design of the source driver should overcome the problem of power consumption.